Preparation and application of reactive ionic liquid flame retardant and flame-retardant polyurethane

Abstract

The invention discloses preparation and application of a reactive ionic liquid flame retardant and flame-retardant polyurethane. The preparation method comprises the following steps: respectively dissolving an acid containing an active group and an organic base in a reaction solvent; the method comprises the following steps: slowly adding an organic alkali solution into an acid solution containing active groups at room temperature or under a heating condition, and stirring to obtain an ionic liquid solution; after the solvent is removed, the reactive ionic liquid flame retardant is obtained; the flame retardant does not contain halogen, phosphorus, metal and other traditional flame retardant elements, preparation is green and efficient, conditions are mild, and operation is easy and convenient; the ionic liquid flame retardant can be connected into a molecular skeleton of polyurethane through a covalent bond to prepare a flame-retardant polyurethane material, and the ionic liquid flame retardant contained in the ionic liquid flame retardant can change the pyrolysis process of carbamate bonds, release carbon dioxide, effectively dilute the concentration of combustibles, remarkably improve the limit oxygen index of polyurethane and greatly prolong the ignition time at a high temperature or in case of fire; the total smoke release amount and the fire spread index are effectively reduced, and excellent flame-retardant and smoke-suppression effects and long-acting durability are shown.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer material flame retardation, and particularly relates to a reactive ionic liquid flame retardant and preparation and application of flame-retardant polyurethane. BACKGROUND

[0002] Polyurethane is a high molecular material containing urethane characteristic units generated by polymerization of polyisocyanate and polyol under the action of a catalyst. It can be made into various products from soft to hard through the types of raw materials and preparation processes, and is used in fields such as construction, automobile, chemical industry, electronics, etc., such as foam, paint, fiber and artificial leather. However, the polyurethane molecular chain is rich in flammable hydrocarbon segments, which can easily ignite and burn in the air, with a limiting oxygen index (LOI) of only about 17%, belonging to highly flammable materials. Under fire or high temperature conditions, the poor thermal stability of the urethane bond rapidly breaks, the polyurethane material melts and drips and forms a pool fire, releasing a large amount of heat and toxic smoke, and is extremely easy to ignite the surrounding materials, bringing serious fire safety hazards.

[0003] At present, the common method to improve the flame retardant performance of polyurethane materials is to introduce a flame retardant into the matrix. Traditional halogen-based, phosphorus-based and nitrogen-based flame retardants, such as dimethyl methylphosphonate, phosphate ester polyol, tris (2-chloropropyl) phosphate, tris (1, 3-dichloroisopropyl) phosphate and melamine, etc., can effectively improve the flame retardant performance of polyurethane, but the LOI is still difficult to break through 26%. The gas phase flame retardant mechanism of halogen / phosphorus-based flame retardants often significantly aggravates the release of smoke and toxic gas. The halogen-containing flame retardant releases hydrogen halide and other strong corrosive gases when burning, and some phosphorus-containing flame retardants have strong biological accumulation and great ecological toxicity, and are facing the limitation and gradual elimination of regulations such as the European Union. On the other hand, the inherent easy migration and precipitation characteristics of the additive type flame retardant result in poor flame retardant durability, and a large amount of addition will deteriorate the mechanical properties of polyurethane. In contrast, the reactive flame retardant can significantly improve the durable flame retardant performance by covalently bonding the flame-retardant structural unit to the polyurethane molecular skeleton. However, the preparation of most reactive flame retardants has problems such as long time, multiple side reactions, difficult separation and purification, and low yield, such as organic chemical reactions such as esterification reaction, nucleophilic substitution reaction, addition reaction, ring-opening reaction, etc. The process is complex and the cost is high.

[0004] Ionic liquids are molten salts composed of organic cations and inorganic or organic anions, which are liquid at or near room temperature. In recent years, they have shown significant potential in the field of flame retardancy. However, most existing ionic liquid flame retardants are still additives, prone to migration and failure during long-term use or processing, and their mechanical properties deteriorate due to plasticization. Chemically, common ionic liquid flame retardants mainly include anionic structures containing halogens (such as chloride, bromide, and tetrafluoroborate) and phosphorus (such as hexafluorophosphate). Their flame-retardant effect still relies on traditional flame-retardant elements, which has significant limitations in terms of environmental safety. Therefore, designing a reactive ionic liquid flame retardant that can chemically bond with a polyurethane matrix without traditional flame-retardant elements to achieve high-efficiency flame retardancy, long-lasting durability, and mechanical reinforcement in polyurethane materials is of great significance. Summary of the Invention

[0005] The purpose of this invention is to at least solve the above-mentioned problems or defects and to provide corresponding technical solutions, the advantages of which will be explained later.

[0006] To achieve these objectives and other advantages of the present invention, a method for preparing a reactive ionic liquid flame retardant is provided, comprising the following steps: Step 1: Dissolve the acid containing the active group and the organic base in the reaction solvent respectively to obtain the acid solution containing the active group and the organic base solution. Step 2: Under room temperature or heating conditions, slowly add the organic base solution to the acid solution containing active groups, and stir the reaction rapidly to obtain an ionic liquid solution; Step 3: Remove the solvent from the ionic liquid solution by means of multi-effect evaporation, mechanical vapor recompression, evaporator or rotary evaporator, and then dry it with a vacuum drying oven, molecular sieve or adsorbent to obtain reactive ionic liquid flame retardant.

[0007] Preferably, in step one, the acid containing the active group is selected from at least one of amino acids, hydroxycarboxylic acids, hydroxysilicic acids, mercaptocarboxylic acids, hydroxysulfonic acids, aminosulfonic acids, hydroxysulfinic acids, hydroxyboronic acids, and aminoboronic acids.

[0008] Preferably, in step one, the organic base is selected from at least one of tetrabutylammonium hydroxide, tetrabutylammonium chloride, tetramethylammonium hydroxide, tetramethylguanidine, triethylamine, 2,6-di-tert-butylpyridine, dimethylamine, choline chloride, choline hydroxide, diethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, methylamine, imidazole, and pyridine, and the reaction solvent is selected from at least one of ethanol and water.

[0009] Preferably, in step one, the concentration of the acid solution containing active groups is 0.01 mol / L to 50 mol / L, and the concentration of the organic base solution is 0.01 mol / L to 50 mol / L.

[0010] Preferably, in step two, the reaction temperature is room temperature - 90°C, and the reaction continues for 0.5h to 2h after the pH stabilizes.

[0011] A reactive ionic liquid flame retardant, wherein the reactive ionic liquid flame retardant is prepared by the above-described preparation method.

[0012] Preferably, the cation of the reactive ionic liquid flame retardant is one or more of alkyl quaternary ammonium ions, alkyl primary amine ions, and nitrogen heterocyclic ions, and does not contain phosphorus, halogens, or metal elements; the anion of the reactive ionic liquid flame retardant is an anion of an organic acid, wherein the organic acid contains at least one carboxyl group and / or sulfonic acid group and / or silicic acid, and does not contain phosphorus or halogen elements.

[0013] A method for preparing a flame-retardant polyurethane material, wherein a reactive ionic liquid flame retardant as described above is added during the polyurethane preparation process; The reactive ionic liquid flame retardant is added at a rate of 0.1 wt% to 30.0 wt% of the total mass of the polyurethane material. The polyurethane material is one of flexible polyurethane foam, rigid polyurethane foam, polyurethane elastomer, or polyurethane coating.

[0014] Preferably, when the polyurethane material is a polyurethane foam material, the preparation method includes: mixing polyether polyol, foaming agent, catalyst, surfactant and the reactive ionic liquid flame retardant evenly, and then reacting it with isocyanate to obtain flame-retardant polyurethane foam.

[0015] Preferably, when the polyurethane material is a polyurethane elastomer, the preparation method includes: introducing a reactive ionic liquid flame retardant as an active component, allowing it to be introduced into the crosslinking network of the polyurethane through chemical bonding, thereby achieving composite composition and obtaining a flame-retardant polyurethane elastomer; When the polyurethane material is a polyurethane coating, the preparation method includes: uniformly dispersing the reactive ionic liquid flame retardant in the polyurethane coating, and then forming a flame retardant coating on the surface of the substrate by spraying, scraping or roller coating.

[0016] An application of a flame-retardant polyurethane material prepared by the above method, wherein the polyurethane material is used in packaging, electronics, construction, home furnishing, chemical, transportation, and aerospace fields.

[0017] The present invention has the following beneficial effects: This invention proposes a novel method for preparing ionic liquid flame retardants. Through the efficient reaction between acidic compounds containing active groups and organic bases, it provides a new approach for preparing reactive liquid flame retardants that do not contain traditional phosphorus, halogen, or metal flame retardant elements. This preparation method is mild, simple to operate, has a high yield, and is environmentally friendly. The resulting ionic liquid flame retardant is liquid at room temperature and exhibits excellent flowability and compatibility. The flame retardant of this invention can be covalently introduced into the molecular chain network of polyurethane, fundamentally solving the migration and precipitation problem of additive flame retardants, and endowing polyurethane with durable and stable flame retardant properties. When polyurethane is heated, the contained organic base ions catalyze the cleavage of urethane bonds, releasing non-flammable carbon dioxide gas, effectively diluting the concentration of combustibles and oxygen, significantly increasing the limiting oxygen index of the material, greatly extending the ignition time, and effectively reducing smoke release and fire spread index. Highly efficient flame retardancy of polyurethane materials can be achieved with extremely low introduction amounts; it does not easily migrate or precipitate under normal, high humidity conditions, exhibiting excellent long-lasting and durable flame retardant properties. The reactive ionic liquid flame retardant of this invention can also effectively enhance the mechanical strength and toughness of materials by promoting the formation of microphase separation structures in the matrix. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can implement it based on the description.

[0019] Example 1 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 0.5 mol of aspartic acid in 150 mL of deionized water to obtain an aspartic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 1 mol of tetrabutylammonium hydroxide in 500 mL of deionized water to obtain a tetrabutylammonium hydroxide solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add tetrabutylammonium hydroxide solution dropwise to aspartic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0020] Example 2 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 1 mol of mercaptoacetic acid in 250 mL of ethanol to obtain a mercaptoacetic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 1 mol of tetrabutylammonium hydroxide in 500 mL of deionized water to obtain a tetrabutylammonium hydroxide solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add tetrabutylammonium hydroxide solution dropwise to mercaptoacetic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent is removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0021] Example 3 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 1 mol of hydroxyethyl sulfonic acid in 250 mL of water to obtain a hydroxyethyl sulfonic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 1 mol of imidazole in 400 mL of deionized water to obtain an imidazole solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add the imidazole solution dropwise to the hydroxyethyl sulfonic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h. Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0022] Example 4 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 0.25 mol of citric acid in 100 mL of water to obtain a citric acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 0.75 mol of tetramethylguanidine in 300 mL of deionized water to obtain a tetramethylguanidine solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add tetramethylguanidine solution dropwise to citric acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0023] Example 5 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 1 mol of lactic acid in 250 mL of deionized water to obtain a lactic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 1 mol of choline hydroxide in 500 mL of deionized water to obtain a choline hydroxide solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add choline hydroxide solution dropwise to lactic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0024] Example 6 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 0.5 mol of glycolic acid in 150 mL of ethanol to obtain a glycolic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 0.5 mol of pyridine in 250 mL of deionized water to obtain a pyridine solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add the pyridine solution dropwise to the glycolic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0025] Example 7 A method for preparing a reactive ionic liquid flame retardant includes the following steps: Step 1: Dissolve 1 mol of glycolic acid in 250 mL of deionized water to obtain a glycolic acid solution, and place it in a three-necked flask equipped with a mechanical stirrer. Separately, dissolve 1 mol of tetramethylammonium hydroxide in 500 mL of deionized water to obtain a tetramethylammonium hydroxide solution, and transfer it to a constant pressure dropping funnel. Step 2: Under continuous stirring, add tetramethylammonium hydroxide solution dropwise to lactic acid solution, control the reaction temperature at 60°C, the stirring rate at 500 r / min, and react for 6 h; Step 3: After the reaction is complete, the reaction solution is transferred to a flask and the solvent and water are removed by rotary evaporation at 50 °C and 90 r / min. The resulting product is then vacuum dried at 80 °C for 48 h to finally obtain the target ionic liquid, namely the reactive ionic liquid flame retardant.

[0026] In subsequent embodiments, the reactive ionic liquid prepared in Example 1 will be used as the flame retardant component of the polyurethane material, and the resulting polyurethane material will be subjected to relevant performance tests. It should be noted that in Examples 8-10 and Comparative Examples 1-2, in addition to the different amounts of flame retardant introduced, the amounts of water, tertiary amine catalyst and isocyanate MDI may vary. The purpose is to control the density of the foam to be the same and to achieve better foaming.

[0027] Example 8 A method for preparing flame-retardant polyurethane using a reactive ionic liquid flame retardant includes: 80 parts by weight of polyether polyol with a hydroxyl value of 35 mg KOH / g, 20 parts by weight of polyether polyol with a hydroxyl value of 24.6 mg KOH / g, 3 parts by weight of reactive ionic liquid flame retardant, 7 parts by weight of silicone oil, 1 part by weight of triethanolamine, 0.9 parts by weight of water, 0.5 parts by weight of cell opener GK-350D, and 0.15 parts by weight of gel-type tertiary amine catalyst dibutyltin dilaurate were sequentially added to a container and stirred at 3000 r / min for 5 min to mix evenly. Then, 35 parts by weight of isocyanate MDI were added, and after high-speed stirring, the mixture was poured into a mold and cured at room temperature for 72 h to obtain flame-retardant polyurethane foam material.

[0028] Performance test results show that, compared with the limiting oxygen index of 18% for polyurethane foam without flame retardant, the limiting oxygen index of this foam material is increased to 24.3%, the ignition time is extended by 900%, the smoke emission is reduced by 38%, the elongation at break is increased by 23%, and the tensile strength is increased by 10%.

[0029] Example 9 A method for preparing flame-retardant polyurethane using a reactive ionic liquid flame retardant includes: 80 parts by weight of polyether polyol with a hydroxyl value of 35 mg KOH / g, 20 parts by weight of polyether polyol with a hydroxyl value of 24.6 mg KOH / g, 5 parts by weight of reactive ionic liquid flame retardant, 7 parts by weight of silicone oil, 1 part by weight of triethanolamine, 0.8 parts by weight of water, 0.5 parts by weight of cell opener GK-350D, and 0.2 parts by weight of gel-type tertiary amine catalyst dibutyltin dilaurate were sequentially added to a container and stirred at 3000 r / min for 5 min to mix evenly. Then, 36.6 parts by weight of isocyanate MDI were added, and after high-speed stirring, the mixture was poured into a mold and cured at room temperature for 72 h to obtain flame-retardant polyurethane foam material.

[0030] Performance test results show that, compared with the 18% limiting oxygen index of polyurethane foam without flame retardant, the limiting oxygen index of this foam material reaches 26.2%, the ignition time is extended by 1008%, the smoke emission is reduced by 36%, the elongation at break is increased by 35%, and the tensile strength is increased by 18%.

[0031] Example 10 A method for preparing flame-retardant polyurethane using a reactive ionic liquid flame retardant includes: 80 parts by weight of polyether polyol with a hydroxyl value of 35 mg KOH / g, 20 parts by weight of polyether polyol with a hydroxyl value of 24.6 mg KOH / g, 7 parts by weight of reactive ionic liquid flame retardant, 7 parts by weight of silicone oil, 1 part by weight of triethanolamine, 0.75 parts by weight of water, 0.5 parts by weight of cell opener GK-350D, and 0.35 parts by weight of gel-type tertiary amine catalyst dibutyltin dilaurate were sequentially added to a container and stirred at 3000 r / min for 5 min to mix evenly. Then, 39 parts by weight of isocyanate MDI were added, and after high-speed stirring, the mixture was poured into a mold and cured at room temperature for 72 h to obtain flame-retardant polyurethane foam material.

[0032] Performance test results show that, compared with the limiting oxygen index of 18% for flexible polyurethane foam without flame retardant, this foam material has a limiting oxygen index of 28.5%, an ignition time that is extended by 1446%, a smoke emission that is reduced by 36%, an elongation at break that is increased by 53%, and a tensile strength that is increased by 73%.

[0033] Comparative Example 1 80 parts by weight of a first-order polyether polyol with a hydroxyl value of 35 mg KOH / g, 20 parts by weight of a second-order polyether polyol with a hydroxyl value of 24.6 mg KOH / g, 7 parts by weight of silicone oil, 1 part by weight of triethanolamine, 1.2 parts by weight of water, 0.5 parts by weight of a cell opener, 0.1 parts by weight of a gel-type tertiary amine catalyst, and 0.08 parts by weight of a foaming-type tertiary amine catalyst were sequentially added to a container and stirred at 3000 r / min for 5 min. Then, 35.3 parts by weight of isocyanate MDI were added, and after high-speed stirring, the mixture was poured into a mold and cured at room temperature for 72 h to obtain a flame-retardant polyurethane foam material.

[0034] Comparative Example 2 80 parts by weight of a first-order polyether polyol with a hydroxyl value of 35 mg KOH / g, 20 parts by weight of a second-order polyether polyol with a hydroxyl value of 24.6 mg KOH / g, 20 parts by weight of a commercial flame retardant: tris(2-chloropropyl) phosphate (TCPP), 5 parts by weight of silicone oil, 1 part by weight of triethanolamine, 1.2 parts by weight of water, 0.5 parts by weight of a cell opener, 0.10 parts by weight of a gel-type tertiary amine catalyst, and 0.08 parts by weight of a foaming-type tertiary amine catalyst were sequentially added to a container and stirred at 3000 r / min for 5 min. Then, 35 parts by weight of isocyanate MDI were added, and after high-speed stirring, the mixture was poured into a mold and cured at room temperature for 72 h to obtain a flame-retardant polyurethane foam material.

[0035] Table 1 Limiting oxygen index / (%) Ignition time / s Cigarette release amount / (m 2 ) Elongation at break / (%) Tensile strength / (kPa) Comparative Example 1 18.0 13 8.9 109.1 60.4 Example 8 24.3 130 5.5 134.1 66.6 Example 9 26.2 144 5.7 168.1 71.4 Example 10 28.5 201 5.7 167.4 104.8 Comparative Example 2 22.5 18 13.2 89.2 54.3 Example 11 This embodiment uses a reactive ionic liquid flame retardant to prepare a polyurethane elastomer: 100 parts by weight of a polyether polyol with a hydroxyl value of 28 mg KOH / g, 5 parts by weight of a small molecule chain extender 1,4-butanediol, 5 parts by weight of a reactive ionic liquid flame retardant, and an appropriate amount of catalyst were thoroughly mixed at room temperature to form a polyol component. Subsequently, this component and the isocyanate component (MDI) were injected into different feed ports of a twin-screw extruder through precision metering pumps, and melt-blended reaction extrusion granulation was carried out at 180°C. The resulting granules were injection molded to obtain a flame-retardant thermoplastic polyurethane elastomer.

[0036] Performance test results show that the limiting oxygen index of this flame-retardant thermoplastic polyurethane elastomer is 27.0%, it achieves a UL-94 vertical burning rating of V-0, and its smoke density is reduced by 26% compared to the system without flame retardants.

[0037] Example 12 This embodiment uses a reactive ionic liquid flame retardant to prepare a polyurethane coating: 100 parts by weight of aliphatic anionic waterborne polyurethane dispersion (35% solids content), 20 parts by weight of silica sol, 1 part by weight of defoamer BYK-024, 2 parts by weight of film-forming aid dodecyl alcohol ester, 4 parts by weight of methylcellulose, 2 parts by weight of polyvinyl alcohol, 0.5 parts by weight of waterborne anti-settling agent hydrophobic modified alkali-swelling thickener ASE-60, 5 parts by weight of reactive ionic liquid flame retardant, and an appropriate amount of water were added sequentially to a beaker and stirred until homogeneous. The mixture was then transferred to a ball mill and ball-milled for 4 hours to obtain a uniform and stable flame-retardant coating. The flame-retardant coating was then applied to the steel surface by spraying to form a 3 mm thick coating film. The coating was allowed to cure at room temperature for 48 hours.

[0038] Performance test results show that the prepared flame-retardant polyurethane film can be continuously sprayed with a butane torch flame (flame temperature of about 1400 °C) for 2 minutes, and the flame will extinguish immediately after the flame is removed from the torch.

[0039] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for preparing a reactive ionic liquid flame retardant, characterized in that, Includes the following steps: Step 1: Dissolve the acid containing the active group and the organic base in the reaction solvent respectively to obtain the acid solution containing the active group and the organic base solution. Step 2: Under room temperature or heating conditions, slowly add the organic base solution to the acid solution containing active groups, and stir the reaction rapidly to obtain an ionic liquid solution; Step 3: Remove the solvent from the ionic liquid solution by means of multi-effect evaporation, mechanical vapor recompression, evaporator or rotary evaporator, and then dry it with a vacuum drying oven, molecular sieve or adsorbent to obtain reactive ionic liquid flame retardant.

2. The preparation method of the reactive ionic liquid flame retardant as described in claim 1, characterized in that, In step one, the acid containing the active group is selected from at least one of amino acids, hydroxycarboxylic acids, hydroxysilicic acids, mercaptocarboxylic acids, hydroxysulfonic acids, aminosulfonic acids, hydroxysulfinic acids, hydroxyboronic acids, and aminoboronic acids.

3. The preparation method of the reactive ionic liquid flame retardant as described in claim 1, characterized in that, In step one, the organic base is selected from at least one of tetrabutylammonium hydroxide, tetrabutylammonium chloride, tetramethylammonium hydroxide, tetramethylguanidine, triethylamine, 2,6-di-tert-butylpyridine, dimethylamine, choline chloride, choline hydroxide, diethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, methylamine, imidazole, and pyridine, and the reaction solvent is selected from at least one of ethanol and water.

4. The preparation method of the reactive ionic liquid flame retardant as described in claim 1, characterized in that, In step one, the concentration of the acid solution containing active groups is 0.01 mol / L to 50 mol / L, and the concentration of the organic base solution is 0.01 mol / L to 50 mol / L; in step two, the reaction temperature is room temperature to 90℃, and the reaction continues for 0.5 h to 2 h after the pH stabilizes.

5. A reactive ionic liquid flame retardant, characterized in that, The reactive ionic liquid flame retardant is prepared by the preparation method according to any one of claims 1-4.

6. The reactive ionic liquid flame retardant as described in claim 5, characterized in that, The cation of the reactive ionic liquid flame retardant is one or more of alkyl quaternary ammonium ions, alkyl primary amine ions, and nitrogen heterocyclic ions, and does not contain phosphorus, halogens, or metal elements. The anion of the reactive ionic liquid flame retardant is the anion of an organic acid, which contains at least one carboxyl group and / or sulfonic acid group and / or silicic acid, and does not contain phosphorus or halogen elements.

7. A method for preparing a flame-retardant polyurethane material, characterized in that, Add the reactive ionic liquid flame retardant as described in any one of claims 5-6 during the polyurethane preparation process; The reactive ionic liquid flame retardant is added at a rate of 0.1 wt% to 30.0 wt% of the total mass of the polyurethane material. The polyurethane material is one of flexible polyurethane foam, rigid polyurethane foam, polyurethane elastomer, or polyurethane coating.

8. The method for preparing the flame-retardant polyurethane material as described in claim 7, characterized in that, When the polyurethane material is a polyurethane foam material, the preparation method includes: mixing polyether polyol, foaming agent, catalyst, surfactant and the reactive ionic liquid flame retardant evenly, and then reacting it with isocyanate to obtain flame-retardant polyurethane foam.

9. The method for preparing the flame-retardant polyurethane material as described in claim 7, characterized in that, When the polyurethane material is a polyurethane elastomer, the preparation method includes: introducing a reactive ionic liquid flame retardant as an active component, allowing it to be introduced into the crosslinking network of the polyurethane through chemical bonding, thereby achieving composite composition and obtaining a flame-retardant polyurethane elastomer. When the polyurethane material is a polyurethane coating, the preparation method includes: uniformly dispersing the reactive ionic liquid flame retardant in the polyurethane coating, and then forming a flame retardant coating on the surface of the substrate by spraying, scraping or roller coating.

10. The application of a flame-retardant polyurethane material prepared by the method described in claim 7, characterized in that, The polyurethane material is used in packaging, electronics, construction, home furnishing, chemical, transportation, and aerospace fields.